GaN-based semiconductors with high breakdown strength are expected to be applied to semiconductor devices for power electronics or high-frequency power semiconductor devices. To realize higher withstand voltage or higher integration, vertical devices with trench structures have been proposed.
Meanwhile, it is difficult to increase activation rates in p-type GaN-based semiconductors. As a result, the contact resistance between a p-type GaN-based semiconductor and an electrode on the p-type GaN-based semiconductor becomes higher.